N = int(input())
C = list(input())

Rn = C.count('R')
print(C[:Rn].count('W')) N = int(input()) N int(input()) int input() input C = list(input()) C list(input()) list input() input Rn = C.count('R') Rn C.count('R') C.count C count 'R' print(C[:Rn].count('W')) print C[:Rn].count('W') [:Rn].count [:Rn] C :Rn Rn count 'W' Rn = C.count('R') C.count('R') Rn C = list(input()) list(input()) C N = int(input()) int(input()) N
N = int(input())
C = list(input())

Rn = C.count('R')
print(C[:Rn].count('W'))